This cable comes with a 3.5mm 4 Pole Jack Plug and 2 x 3.5mm Sockets, which allows you to connect a Microphone and Set of Headphones to a Single Device. Effectively you would plug the 3.5mm into a Mobile Phone or a similar 4 Pole Device and in turn it gives you 2 sockets, one for the Left and Right Stereo Headphones (Green) and the other for Microphone (Red).